Jig for the alignment of pistons and piston connecting rods



July 28, 1925. K. R. WILSON JIG FOR THE ALIGNMENT PISTONS AND PISTON CONNECTING RODS- Filed Dec. 13, 923

2 Sheets-Sheet 1,

July 28, 1925. 1,547.279

K. R. WILSON 316 FOR THE ALIGNMENT OF PISTONS AND PISTON CONNECTING RODS Filed Dec. 13, 1923 2 Sheets- Sheet 2 Eg. 6'. v E8 .7.

I I 7 1 N v a I I '56 i V I. J 7 "5 \4 my MLSOM Patented July 28, 1925.

unis!) sir ,iiinrzn writs-on, or BUFFALO; NEW yank.

m we T mmeiii ir l i pwi in er ate-m ria re Application fiIed DecempcrB, 1923. SeriaL No: 680,341.

New York, have invented a new and useful Improvement in Jigs for, the Alignment of Pistons and Piston Connecting Rods, of which the following isa specification.

This invention relates to improvementsin Jigs for the alignment of pistons and piston connecting rods. It is essential to the satisfactory operat on-0f internal combustion engines; that the pistons be true in forma-- tion andthatthey travel exactly in the direction of their longitudinal axis. surface of thepiston be out oftrueor if its axis be inclined with reference to the directionof piston movement the piston is said tobe cocked and cocked pistons result in piston slapspr knocks, pumping .Of oil, and the scoring of the cylinders. Such cocking of the piston may be due to the de formation of the piston, to the inaccuracy of itsjfit upon the 'c'onnectingpin, to the distortion of the connecting rod or to a, combinationof these causes;

Inorder to, insure satisfactory results 1in the operation of the motorit is, therefore necessary that both the piston and its connecting rod be tested, whereby any defectswhich exist, in the respects ,noted,ma-y be ascertained and corrected. 4 forsuch tests is 'well known but'heretofore so far as I am aware, the means employed has-been open to objection in one particular or another, some of the devices being too elaborate and costly in their equipment, some being diflicult to use, particularlywith a view to absolute accuracy of results, and some failing to insure accuracy.

The object of the present invention is, therefore, to provide an extremely simple and inexpensive ig which will be available for testing both connecting rods and pistons and which by. its novel structural features prescribes a facile mode of, use by which absoluteaccuracyof result can be ob? tained.

Vith this object in view the invention consists in certaln novel details of. struc-' If the The necessity I drawings,

Figure l is a side elevation of the nprie em io' the-fiei igure 2 is a front view thereof.

Figure is a fragmentary rear view thereof showing more particularly the means for. the, adjustment of; the" piston s ingnini i e igure 4 is a front elevation of a gage plate or templet' used in testing the alignment of the connectingrod. A H i Figure 5 is a plan view thereof.

Figures 6 and are rejspectively a side eleyation and a plan view showing tli'e jig as used for testing the alignmenfliof a connecting rod, the rod showing a true align ment Figure 8 is aside elevation showing the jig. as used for testing thelalignment" of a: connecting red, the rod showinga distortion. I 4' V 7' Figure 9 isa side eleyatio n showing'fthe jig asaised for testing a piston, the piston showing, true. cylindrical conformation and true alignment,

'FigurelO is a side elevation showing the jig as used ,for testing the piston, the test showing the piston-to be. out ofalignrnent.

The. complete jig consists, or threegessential, parts, namely, an npright supporthA, an arbor B and'a gage-plate;ortemplet C, all three ofithese parts are used-for testing the alignment of the connecting rod, whereas the gageplate C is not directly used in testing the form and alignment f: the piston. The connecting rodis tested first and if it' isfound to; be out of alignment-it is restored to true alignment. he connecting rod whose trne alignment has thus been ascertained; is then fitted to the piston and thereafter tliepiston,is tested. Any lack of.

alignment which the piston may showgwill thereby not be, attributed toLany fault in the piston rod but .to the deformation ofthe piston or" its. inaccurate centering on its pin. The support Ais formed at its lower end' with suitably extended flat I basev1 by which said support may havea stab1ebear= ingfupon aflbe nch, or table. At its npper ,end the support'A- is formed with a gage plate whose Working, face lies in a vertical plane; The part of the support which carrieslthe plate 2 rnay be ertically adjustable relatively to the base 1 for it m'ay, be integral with the part which carries thebase 1, the integral construction 1 being shown. The

only advantage of the vertical adjustment is that it gives the jig a somewhat wider range of use, making it adaptable to connecting rods of various lengths. The plate 2 may have a continuous working face or it may, as shown, be in the form of a series of blocks 2, whose faces are co-planar, such blocks constituting the functional equivalent of a continuous plate and being suitably arranged for the purposes in View. At a point above the base 1 the support A is provided with a horizontal bore 8 extending between its front and rear faces and in which is removably fitted the arbor B. The gage plate or templet C may have a continuous working face or, as shown it may be provided with a series of blocks 0 whose faces are co-planar and which correspond in number and arrangement to the blocks 2*. The plate C is provided with a centrally located pin 4: which extends at a right angle to the common plane of the faces of the blocks 0 and is available for securing said plate to the connecting rod to be tested.

The operation of testing the connecting rod is shown in Figures 6, 7 and 8. The connecting rod r is clamped by means of its bearing upon the arbor B at a point suitably located between the ends of said arbor, and the post 4 of the plate C is fitted in the collar r at the upper end of the connecting rod. The post 4 engages in the collar r in the manner of the wrist pin of the piston and is suitably secured in position, a clamp 5 engaging over the lugs of the collar r being shown for this purpose. With the plate C confronting the plate 2 the arbor B is then inserted in the bore 3 of the support A and is moved inward in said bore until the plate G contacts the plate'2. If the rod r be free from distortion all of the blocks 0 will engage uniformly against the blocks 2 so that no light will be visible between the engaging faces of any of said blocks. This condition is illustrated in Figures 6 and 7 and the uniform engagement of all of the blocks 0 with all of the blocks 2 is an indication that the connecting rod is in perfect alignment. If however the rod 7* be bent the plate G will be correspondingly canted and one or more of the blocks 0, according to the direction of the bend in the rod 1-, will be spaced from the corresponding blocks 2 so that light will show between the faces of the non-engaging blocks. This condition is i1- lustrated in Figure 8 and the presence of a bend in the rod is thereby indicated, the ex tent and direction of the bend being determined by the location of the blocks a which are not in engagement with the corresponding blocks 2* and by the degree of their separation from such corresponding blocks. When a bend in the rod 1' is thus detected the rod may be straightened by means of a wrench or a suitable bending tool and the testing and rod straightening operations will be repeated until a perfect alignment of the rod is established by a test meeting the conditions above described and as shown in Figure 6.

When the perfect alignment of the con necting rod has thus been ascertained the test of the piston may be made. The previously tested connecting rod is removed from the arbor B and fitted by means of its collar r in working position upon the wrist pin of the piston. The arbor B, according to the invention, is made double length whereby with the connecting rod arranged at the exact center thereof either end of the arbor may be inserted in the bore 3 for the purpose to be later described. To facilitate the location of the connecting rod on the arbor with reference to the piston test the arbor is preferably provided with annular grooves or scorings 6, whose spacing corresponds to the width of the bearing 7 of the connecting rod and which are located equidistant from a point central of the length of the arbor. The connecting rod carrying the piston P is then fitted upon the arbor and secured by its bearing 1 in a position in which the sides of said bearing coincide with the grooves or scorings 6. In order to obtain certainty of results, i. e., to insure the accuracy of the test, the piston should be tested at diametrically opposite points. This is facilitated by providing the arbor B of double length so that the portions thereof at either side of the connecting rod will be available for engagement in the bore of the support. Thus when the piston has been tested at one side the arbor may be withdrawn and inserted in reverse position in the bore 3 whereby the piston may be tested at the opposite side.

The portions of the piston above the first upper piston ring groove are of slightly less diameter than the body of the piston below said groove, the Variation being different for different engines and being dictated by the fact that the upper portion of the piston is subject to greater heat and consequent expansion than the main body. In order to i obtain absolute accuracy of result the test should be made both as to "the main body of the piston and as to its portion of reduced diameter and in order that such test may be encompassed in a single operation the plate 2 is provided, according to the invention, with a projection 7 standing out beyond the faces of the blocks 2* by a distance equal to half of the difiercnce in diameter between the main body and the reduced portion of the piston, the projection 7 being located at an elevation whereby it will engage the shoulder 7) above the first upper piston ring. The gage piece C is in any case formed on its engaging face with a l suitable clearance for the projection '7. In Figures 9 and 10 of the 'drawings the difference in diameter between the shoulder p and the'main body of the piston has necessar'ily'been greatlyexaggerated since in actual practice it cannot be apprehended except with a measuring instrument thus in'one of'the well known makes of automobile engines the shoulder p'is- .005 inch less in diameter than the main body of the piston and for use with such-a piston the projection will extend .0025 inch beyond the common plane of the Working faces of the blocks 2*. While the projection 7 maybe fixed its utility in such case will be limited to pistons having a corresponding variation between the diameters of their main-bodies and the shoulder p. It is therefore prefer; ed that the projection 7 be adjustable in order that; it may be adapted to the different diametrical variations of the different makes of pistons. For this purpose said projection is preferably formed at one end of a screw stem 8 (Figure 1) which has threaded engagement in a socket 9 open to the rear face of the support A and which carries an operating head 10 mounted in a ring 11 cast with or secured to saidsupport. The head 10 has on its outer face a suitable annular scale 12 and co-operates witha fixed index mark 13 on the adjacent face of the ring 11. It will be obvious that the degree to whichthe projection 7 extendsbeyond the working faces of the blocks 2 can be varied by turning the head 10 and will be indicated by the co-operation of the index mark 13 and the scale 12. lVhen the projection 7 has been set to the position desired it is secured against movement by a lock screw 14 engaging the head 10, the screw 14 being threaded through a lug 15 which is formed as an extension from the ring 11. In the operation of testing the piston the arbor B is inserted into the bore 3 until its further inward movement is prevented by the contact of the piston with the plate 2. A perfectly formed and perfectly aligned piston will, as tested at opposite sides thereof, have its main body portion in uniform contact with the adjacent block 2 and its reduced portion p In contact with the portion 7. This condition, for one side of the piston, is shown in Figure 9; and after the test of one side of the piston with the positive results shown in Fig ure 9 the arbor B, without unfastening the connecting rod, is withdrawn and reversed and again inserted into the bore 8 in like manner for a similar test on the opposite side of the piston. If the piston be cooked or be not truly cylindrical it will not umformly contact the adjacent block 2 and the projection 7 and light will show between the face of the piston and the faces of either said block or said projection or both. If this condition appears in a test of either the line 'Yand the axis'of the piston by'thei line Z. It will be seen that the axis X and Y are at right angles but that the axis Z which should coincide with the axis Y is tilted at an angle thereto. Theinaccurate centering of the piston on its wristpin may be due to unequal wear of the bushings orto irregularity in their fitting. If the piston be accurately centered on the wrist pin and a further test should show ateither side of the piston a lack of engagement-or an-'imperfect engagement between thesame and the adjacent block 2 and projection 7. an indication will thereby be given that the piston is not truly cylindrical. It will be'note'd.

that any defects developed by the t est'showu in Figure 9 may-always be attributed to the piston, in either of the respects' notedfsin'ce the perfect alignment oftheconne'cting rod was previously established by the test shown in Figure 6.

From the foregoing it will be seen that I have provided a jig which is simple and inexpensive in its structural makeup, which can be used with facility for testing both connecting rods and pistons and which provides for testing operations of such character that certainty of result can be ob tained and absolute accuracy in the fitting and alignment of the connecting rods and v pistons can be effected.

Having fully described my invention, I claim:

1. A jig for testing the alignment of pistons and piston rod connections including an upright support provided at its front side with a vertically presented gage plate and having a horizontal bore extending between its front and rear faces at a point beyond said gage plate, and an arbor which is removably fitted in said bore and upon which a piston connecting rod may be mounted, said arbor being of double length whereby with the piston connecting rod mounted approximately centrally thereof either of the arbor portions at opposite sides of said connecting rod may be inserted in said bore without disconnecting the piston connecting rod from said arbor, thereby to enable opposite sides of the piston to be tested by said gage plate.

iii!) 2. A jig for testing the alignment of pistons and piston rod connections including an upright support provided at its front side with a vertically presented gage plate and having a horizontal bore extending between its front and rear faces at a point beond said gage plate, an arbor which is removably fitted in said bore and upon which a. piston connecting rod may be mounted, and a projection standing out from the face of the gage plate to engage a portion of the piston of reduced diameter, said arbor being of double length whereby with the piston connecting rod mounted approximately central thereof either of the arbor portions at opposite sides of said connecting rod may be inserted in said bore, thereby to enable opposite sides of the piston to be tested by said gage plate.

3. A jig for testing the alignment of pistons and piston rod connections including an upright support provided at its front side with a vertically presented gage plate and having a horizontal bore extending between'its front and rear faces at a point beyond said gage plate, an arbor which is removably fitted in said bore and upon which a piston connecting rod may be mounted, a projection standing out from the face of the gage plate to engage a portion of the piston of reduced diameter, and gage piece structurally independent of said support for cooperation with the face of said gage plate,

said gage piece being formed to provide clearance for said projection and having a tons and piston rod connections including an upright support provided at its front side with a vertically presented gage plate and having a horizontal bore extending between its front and rear faces at a point beyond said gage plate, an arbor which is removably fitted in said bore and upon which a piston connecting rod may be mounted, a projection standing out from the face of the gage plate to engage a portion of the piston of reduced diameter, said arbor being of double length whereby with the piston connecting rod mounted approximately central thereof either of the arbor portions at opposite sides of said connecting rod may be inserted in said bore, thereby to enable opposite sides of the piston to be tested by said gage plate, and a gage piece structurally independent of said support for co-operation with the face of said gage plate, said gage piece being formed to provide clearance for said projection and having a projecting post by means of which it may be secured to the end of the connecting rod mounted on said arbor.

In testimony whereof I affix my signature.

KIRKE R. WILSON. 

